The Supreme Court has dismissed a bid by WikiLeaks founder Julian Assange to reopen his appeal against extradition to Sweden over alleged sex crimes.

Seven judges of Britain's top court unanimously dismissed the move by Mr Assange as being "without merit".

Two weeks ago the court rejected his argument that a European arrest warrant for extradition was invalid.

His lawyers had argued that the decision was based on a legal point that had not been argued in court.

Swedish prosecutors want to question Mr Assange over allegations of rape and sexual assault made by two female Wikileaks supporters in mid-2010 but have not filed any charges.

Mr Assange, whose WikiLeaks website has published a mass of leaked diplomatic cables that embarrassed several governments and international businesses, claims the sex was consensual and that the allegations against him were politically motivated.

'Last attempt'

The court has given Assange a two-week grace period before extradition proceedings can start.

Once the fortnight is over, officials have 10 days to fly Mr Assange to Sweden.

The BBC's legal correspondent Clive Coleman says this is "pretty much the last attempt" by Mr Assange to legally fight extradition.

The anti-secrecy campaigner could still take his case to the European Court of Human Rights (ECHR) in Strasbourg and has until 28 June to make the move.

Our correspondent says there is the possibility of an appeal to the ECHR but legal experts say that it is "unlikely to block" Mr Assange's extradition.

"Although Sweden is rightly proud of its justice system, its over-use of pre-trial detention means that, if extradited, he is likely to be imprisoned and placed under extremely restrictive conditions."